Reversible drive mechanism



April 26, 1966 v. A. BARNHART I REVERSIBLE DRIVE MECHANISM Filed Oct. 16, 1965 INVENTOR 59PM/wer ArroE/E Y;

BY MM2. Mia@ RELAY y" v United States Patent O 3,247,752 REVERSIBLE DRIVE MECHANISM Vilas A. Bamhart, Waupaca, Wis., assignor to A. E. Moore Company, Inc., Waupaca, Wis., a corporation of Wisconsin Filed Oct; 16, 1963, Ser. No. 316,740 3 Claims. (Cl. 74-89) switch are conventional and the present invention contemplates no change therein. It is also conventional to incorporate in such a circuit a motor reversing switch. In the past, such a switch has had to lbe designed to carry relatively heavy current if its contacter might be shifted from forward to reverse or vice versa while the starting circuit is closed.

By way of exemplifying one area of utility of the present invention, the disclosure relates to `a screw such as is used in a garage door operator, being required to alternate its direction of rotation in successive operations.

These are many other applications similarly requiring reversal of direction every time a driven shaft is operated. Since it may be desirable to reverse the direction of the driven part immediately, without awaiting completion of any predetermined range, the reversing switch should be activated in anticipation of the next direction of movement almost immediately after one operation starts. At the instant of starting, however, the circuit in which the reversing switch is used is carrying a heavy current. The present invention initiates a train of motion transmission immediately but defers the actual actuation of the switch briey to allow the motor to reach normal speed and the circuit to open. This relieves the reversing switch contacts of arc and destructive burn.

My lost motion accumulator comprises a serie-s of tumbler disks on a motor driven shaft. One of these serves as a driver and has friction slip-clutch connection with the shaft. Each disk has a peripheral lug which, after nearly 360 of rotation, will engage the lug of the next disk. Assuming there are four tumbler disks, the shaft will make nearly four complete revolutions before the last disk will move.

i The final disk is an operator for the reversing switch. The switch is conventional, having a toggle lever actuator. The disk has a notch in which the end of the lever is disposed. Initial lever actuating pressure is on the end of the lever, thus making maximum leverage available for throwing the switch. However, for arresting tumbler disk rotation, the terminal disk of the series has broad flaring surfaces for engaging the side of the lever for a substantial part of its length, including a lever portion close to its fulcrum. The actuation of the lever is very positive. Yet when the lever reaches its reversed position and stops, the engagement ofthe surfaces of the final disk occurs so close to the lever fulcrum that the disk has little remaining leverage. The whole series of disks thereupon also comes to rest, the slip-clutch permitting the disks to remain at rest during continued shaft rotation in the same direction.

In this position of the switch, the next motor operation will drive the shaft in the opposite direction. Again the disks will permit a number of shaft rotations before the switch reverses. Since the drive ratio between the 'motor andl shaft permits a much greaternumber of armature shaft rotations before the -switch is actuated, the motor will have ample time to reach full speed and its starting circuit will have opened before the reversing 3,247,732 Patented Apr. 26, 1966 switch is thrown. Thus the reverser will function only when its circuit is open.

In the drawings: i

FIG. 1 is a diagrammatic view in side elevation of a device employing the invention.

FIG. 2 is a fragmentary detail view in perspective of a motion accumulator comprising a series of tumbler disks on a shaft.

FIG. 3 is a fragmentary plan view ofthe mounted tumbler disks.

FIG. 4 is a view in section on the line 4-4 of FIG. 2 showing the switch actuating terminal ring and the reversing switch actuated thereby.

FIG. 5 is a fragmentary detail view showing the shaft in section and the driver ring in elevation.

FIG. 6 is an exploded view showing the several tumber disks in perspective and in mutually separated positions.

FIG. 7 is a simplied wiring diagram.

The motor 10 is diagrammatically shown to be mounted on arms 12 depending from a bearing member 14 in which driven shaft 16 is rotatably mounted. The shaft has a screw extensionlS along which nut 20 moves forth and back according to the directionV of rotation of shaft 16. The motor armature shaft 22 has a small pulley 24 connected by bel-t 26 with a larger pulley 28 on shaft 16, thus providing a reducing drive for assuring an .adequate num- `ber of rotations of the armature shaft to permit it to get up to speed by the time the reversing switch is operated by means now described.

On shaft 16 is a series comprising any desired number of tumbler disks. As shown, the series comprises a driver 30 and a driven switch actuator 32 and intervening disks 34, 36 and 38. The driver 30 is a split ring frictionably engaged with shaft 16 and contracted thereon by a spring 40. Itcarries a lug 42 overhanging disk 34 for interaction with a lug 44 with which disk 34 is provided. Lug 44, in turn, overhangs disk 36 for engagement with its lug 46. Lug 46 interacts with lug 48 of disk 38 and lug 418 engages lug 150 of switch `actuator disk 32. When the driver changes direction, each disk in turn will pick up the next disk in the series after nearly one full rotation.

Switch actuator disk 32 has `a deep notch 52 that receives the switch lever 54 of reversing: switch 56. The divergent surfaces 58, 60 flare at an angle such as to engage the lever 54 close to its outer end (for adequate leverage) but also close to its fulcrum, as shown in FIG. 4, to minimize the torque exerted on the lever when it reaches either of its extreme positions. The whole set of tumbler disks is held stationary by the switch lever, once the lever is thrown. This does not overload the switch lever because of the reduction in leverage achieved by the design above described. The shaft continues to rotate, of course, the driver 30 slipping on the shaft to accommodate shaft rotation.

In the simplified wiring diagram, the motor 10 is shown provided with a running winding at 62 and a starting winding at 64 and a conventional centrifuga-Hy operated switch at 66 for opening the circuit to the starting winding after the motor arrives at running speed. The reversing switch 56 is represented diagrammatically. It is relieved of the load of the starting winding when switch 66 is open.

The starting switch 68 closes a circuit from the transformer 70 to energize the relay 72 which is a device known commercially as a latching relay, meaning that it latches in extreme position in respose to an impulse of current, being released to return t-o its opposite position when the next impulse reaches it. The impulse created by the closing of the starting switch 68 causes the relay to attract armature 74 to close the grounding and motor circuits respectively controlled by contactors 76 and 78. The grounding circuit is deenergized except when the relay circuits are closed to operate the motor. This is a safety feature. W-hen the nut 20 reaches either extreme of its motion, it engages one or the other of the stationary contact pairs 80 or 82 to send an impulse through ground to the relay, thereby permitting the latching relay 72 to return to its original open circuit position. This stops the motor 10 and also opens all circuits, including those to the spring contact pairs 80 and 82.

I cla-im:

1. In a device of the character described, the combination with a reversing mechan-ism having an actuating lever pivoted for limited oscillation between two extreme positions, of a lost motion actuator for said lever including the combination with `a reversibly rotatable shaft, of a series of tumbler rings rotatably mounted on the shaft, a ring at one end of the series having frictional connection with the shaft to receive motion therefrom, a ring at the other end of the series having a generally radial notch in which said lever is disposed and having surfaces bounding said notch normally engaged with said lever remote from its pivot and which flare angularly and are positioned to engage said lever close to its fulcrum point in each of the respective extreme positions of oscillation of said lever, the rings of said series having shoulders engageable for the transmission of motion from one of said rings to the next ring of the series after predetermined angular movement with said shaft.

2. In a controlled dev-ice for throwing a reversing switch after a predetermined rotation of a reversible driven shaft, such switch having a lever mounted for limited angular oscillation between two extreme positions, the combination with said reversi-bly rotatable shaft, of a series of tumbler rings rotatably mounted on the shaft and having peripheral lug portions for the transmission of rotative motion from one ring of the series to a consecutive ring of the series after predetermined rotal tion of said one ring with the shaft, means for frictionally connecting a ring at one end of the series to receive motion from the shaft, and means for transmitting motion from a ring at the other end of the series to said lever for the oscillation thereof from one extreme of its movement to the other eXtreme thereof following each reversal of direction of shaft rotation, said last means comprising a terminal disk having a radial notch in which the end of said lever is engaged, said terminal disk further having aring surfaces extending from opposite sides of the notch and so positioned that one such surface is disposed to engage one side of said lever at points close to the fulcrum of said lever in each of the extreme positions of said levers, whereby to arrest the movement of said disks and permit continued rotation of the shaft without imposing undue stress on said lever, reversal of shaft direction causing the rst disk of the series to .be driven frictionally for a substantial angular distance before imparting angular rotation to another ring of said series until the terminal disk of said series ultimately effects oscillation of said lever from one extreme position thereof to the opposite extreme position thereof, the end of said lever being initially engaged by said terminal disk and a portion of the lever adjacent the fulcrum References Cited by the Examiner UNITED STATES PATENTS 2/1950 Elliott 74-10.2 6/195'8 Perlis 74-102 X BROUGHTON G. DURHAM, Primary Examiner.

F. E. BAKER, Assistant Examiner. 

1. IN A DEVICE OF THE CHARACTER DESCRIBED, THE COMBINATION WITH A REVERSING MECHANISM HAVING AN ACTUATING LEVER PIVOTED FOR LIMITED OSCILLATION BETWEEN TWO EXTREME POSITIONS, OF A LOST MOTION ACTUATOR FOR SAID LEVER INCLUDING THE COMBINATION WITH A REVERSIBLY ROTATABLE SHAFT, OF A SERIES OF TUMBLER RINGS ROTATABLY MOUNTED ON THE SHAFT, A RING AT ONE END OF THE SERIES HAVING FRICTIONAL CONNECTION WITH THE SHAFT TO RECEIVE MOTION THEREFROM, A RING AT THE OTHER END OF THE SERIES HAVING A GENERALLY RADIAL NOTCH IN WHICH SAID LEVER IS DISPOSED AND HAVING SURFACES BOUNDING SAID NOTCH NORMALLY ENGAGED WITH SAID LEVER REMOTE FROM ITS PIVOT AND WHICH FLARE ANGULARLY AND ARE POSITIONED TO ENGAGE SAID LEVER CLOSE TO ITS FUL- 